Update Section Label to use correct colour in secondary column

[simonsinclair]

Is your feature request related to a problem? Please describe.

Titles in the secondary column are created using psammead-section-label, which uses a link a colour (EBON). When used in the secondary column, these are not links and therefore should use #3F3F42 (SHADOW).

Describe the solution you'd like

• Update psammead-section-label component to use colour EBON if the section label is a link and SHADOW if it's not.
• Ensure this change reflects correctly in the secondary column.

Note: This may require raising a Psammead issue. Whoever picks this up can create this if it's needed.

Describe alternatives you've considered

n/a

Testing notes

[Tester to complete]

Dev insight: Will Cypress tests be required or are unit tests sufficient? Will there be any potential regression? etc

• This feature is expected to need manual testing.
• This feature is expected to have a UX review.

Additional context

n/a